The inventors of this application have previously proposed a vane-type rotary compressor provided with a rotary sleeve interposed between a center housing and a rotor, under Japanese Patent Application No. 56-162025 (JP, A, 58-65988). The compressor is particularly suitable for use with an automobile engine required to operate over a wide speed range because of being substantially free from frictional heat as well as wear at the apex of each vane. However, there is the possibility of scuffing and seizure troubles if air is highly compressed in the compression working space within the compressor to push the rotary sleeve from within to the inner periphery of the center housing.
From a study on the movement of the rotary sleeve, it has been clarified that a contact between the rotary sleeve and the center housing possibly takes place at not a specific line but a relatively wide zone. The inventors have proposed under patent application No. 58-28608 (JP, A, 59-155589) that the air inlet is provided at the starting line of the contact zone in which the contact is likely to occur and internally connected to one of the open air, the discharge chamber, and the compression working space under the maximum pressure to increase an amount of air flowing over the contact zone and improve the bearing effect of the air-bearing room. However, there has remained a problem that the bearing effect is not uniformly raised, that is, high in the center but low in the opposite ends, resulting in that the rotary sleeve has the opposite ends unbalanced in the air-bearing room.
It is the primary object of the invention to provide a rotary sleeve supporting apparatus in which the rotary sleeve has the opposite ends thereof well balanced when air is supplied into the air-bearing room to increase an amount of air flowing about the rotary sleeve.